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Gas Giant

The answer is definitely Jupiter throughout October. Have you noticed the solar system’s largest planet in the night sky this month? In the last few weeks, Jupiter rose in the late evening, climbing higher into the heavens and dominating the sky. Early risers can also see Jupiter before dawn, approximately 60 degrees above the horizon in the constellation of Taurus the Bull.

This bright gaseous giant is worth a look! Jupiter is the fourth brightest object in the sky after the sun, the moon, and Venus. Its many features warrant closer examination. A telescope is best to see this planet’s fabulous features.

Jupiter’s impressive size belies its composition. While we would not want to be part of this crowd, Jupiter doesn’t mind one bit being one of the gas giants. The other gas giants, known as the Jovian planets, include Saturn, Uranus and Neptune. Contrast those to the more solid terra planets, which comprise Earth, Venus, Mars and Mercury.

A surface made exclusively of gas is Jupiter’s brag. Ninety per cent hydrogen and 10 per cent helium make up most of the planet’s exterior, but within there’s an inner core of metal and rock.

Even if all eyes are on Jupiter, its own large eye is roving. This planet’s most interesting surface feature is its Great Red Spot, which is actually an anti-cyclonic storm more than two times larger than the earth. This stormy spot rotates counterclockwise every six days at a speed of 225 miles per hour.

Wind and rotation also cause the multi-colored stripes that appear in Jupiter’s atmosphere. From pole to pole, the planet takes on the multi-colored look of the Gay Head Cliffs. These layers of colors are caused by dark belts and light zones, each containing differing chemical makeup, created by powerful east/west winds in Jupiter’s atmosphere. There are white-colored cloud bands, for instance, which are made up of frozen ammonia gas.

Above the surface of Jupiter are its planetary rings. Hardly as spectacular as Saturn’s rings, they were revealed by NASA’s Voyager 1 spacecraft mission in 1979. Three circle the planet and include an inner halo, a bright main ring and an outer gossamer ring.

But that’s not all. This planet also boasts more than 65 natural satellites or moons. The four largest of the moons, Io, Europa, Ganymede and Callisto, are known as Galilean moons, because Galileo discovered them through the newly-invented technology of the telescope. Jupiter was named after the Roman god Jupiter, or Jove. That is the name that stuck in Western science, but the Greeks called the same planet Zeus. The planet was also known to the Egyptians, Babylonians and the ancient Chinese. The moons around the planet were named after figures in Zeus’ life, mostly his lovers. With 65 and counting, he must have had a very busy social life!

According to NASA, the spacecraft Galileo plunged (as intended) into Jupiter’s crushing atmosphere on Sept. 21, 2003, sending data all the way. Before doing so, it made a tour of those moons, during which it “found evidence of subsurface saltwater on Europa, Ganymede and Callisto and revealed the intensity of volcanic activity on Io.” In fact, NASA believes that Europa possesses more water than the total amount found on Earth!

So, when we look at the gas giant in our sky on these October evenings (or mornings), we are possibly, or even probably, looking at a future vacation destination for human space travelers. Who wouldn’t want to take a swim in the waters of Europa? Jupiter’s huge mass and gravitational field will even help pull us there. It makes sense, since Jupiter has drawn our eyes and attention to it all throughout history. Why not our space ships as well?

Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown.